This invention generally relates to a machine that automatically assembles, inspects, and packages dental products and, more specifically, disposable prophylaxis angles.
Dentists and hygienists have used prophylaxis (prophy) angles for over 100 years to clean and polish teeth. Until recently, prophy angles were made of metal so they could be used over and over again, one patient after the next. To prevent the spread of infectious diseases from patient to patient, the dentist or hygienist cleaned and sterilized the angle after each use.
In recent years, a market has developed for disposable prophy angles due in part to increased awareness and concern for the spread of infectious diseases such as hepatitis and AIDS. Because disposable prophy angles are discarded after each use, they must be produced in extraordinarily greater quantities than the metal angles they have replaced. As a result, a need exists to develop cost-effective processes for manufacturing disposable prophy angles in large quantities.
There are three basic steps in the production of disposable prophy angles: the manufacture of the components of the angle, the assembly of the angle components, and the packaging of the assembled angles. The packaging step can be further subdivided into individual bagging, batch counting, and carton sealing.
The manufacture of individual angle components is already highly mass produced through means such as injection and compression molding, the prior means being the dominant method. The assembly step, however, is done largely by hand since automated machinery for prophy angle assembly is not available. Such equipment must be designed specifically for this. The batch-counting step is also performed largely by hand since this equipment must also be designed specifically for this purpose and because, to be practical, it must be integrated with other automated machinery. Carton sealing equipment, although readily available, must also be integrated with other automated machinery in order to be practical.
While the assembly of prophy angles by hand has the advantage of requiring minimal initial investment; it has several inherent major disadvantages. Lubrication on the bearings and gears of disposable prophy angles provides smoother operation and increased life. Yet, when done by hand, this step can be somewhat difficult and add a significant amount of time, and therefore cost, to the assembly operation. Controlling the amount of lubricant applied in hand assembly can also be difficult. An angle that is under-lubricated may run less smoothly or overheat when used. Lubricant may leak out of an over-lubricated angle making it messy for the end user, and ultimately the patient in whose mouth the device will be used.
Another disadvantage is the variability in quality of the finished product. Due to the repetitious nature of assembly by hand, it is often difficult for assembly personnel to remain focused on their work. For this reason, along with the fact that large numbers of assembly personnel are required, variability in the quality of the finished product, especially related to the application of lubricant, is a constant problem.
All of the disadvantages above add to the cost of hand-assembled disposable prophy angles in order to ensure that they are clean, safe, and high quality.
The present invention is directed to a machine and method for assembling a dental product. The dental product generally includes a body, first and second gears, and a tool. The machine comprises feeders for automatically supplying the component parts and contiguous assembly stations coupled to the feeders for receiving the component parts and for performing assembly steps of the dental product. The assembly stations comprise a body station for receiving and holding the body of the product, at least two gear stations for introducing the first and second gears of the dental product into the body, and a tool station for connecting the tool to the second gear of the dental product. In a preferred embodiment, the machine further comprises a lubricating station for applying lubricant to the gears of the dental product.
In other preferred aspects of the invention, automated bagging and packaging equipment is provided. For this aspect of the invention, the machine comprises a first conveyor for automatically moving assembled angles to a bagging unit. The bagging unit automatically bags the assembled angles. The machine also preferably includes a batch-counting unit for automatically counting a batch of assembled and bagged dental products and placing the batch in a container.
A second conveyor is provided for moving assembled and bagged dental products from the bagging unit to the batch-counting unit. The machine preferably includes a batch conveyor system comprising a first accumulating conveyor for supplying containers to the batch-counting unit and a second accumulating conveyor for moving a container with the batch to an unloading station. The machine can also include a carton-sealing unit for sealing the container. The carton-sealing unit is preferably located on the second accumulating conveyor, prior to the unloading station.
A method of assembling a dental device with automated machinery is also disclosed herein. The dental device has a body and at least two gears. The body has a first end adapted to receive a drive mechanism for turning the gears of the dental device and a second end for holding a dental tool. The second end has a closure for closing off the second end of the dental product. The method for automatically closing the body of the dental device after the gears have been introduced into the body comprises the steps of receiving the body of the angle with gears loaded into the body. The body is located on a mounting post that engages the first end of the dental device to hold it. The method also comprises closing the body of the dental device by using a mechanism that snaps the closure to a closed position to close off the second end of the angle. In a preferred aspect of the invention, the method specifically comprises closing the dental device by engaging an outer surface of the closure and rotating it to the closed position.
In another aspect of the invention, the method of assembling the dental product comprises the steps of transferring the body of the dental device from a body feeder to a moveable table and advancing the table to move the body to a first gear loading station and loading the first gear into the body. The method further comprises advancing the table to move the body to a second gear loading station and loading the second gear into the body and advancing the table to move the body to a closure station and closing the body of the dental device. Finally, the method comprises advancing the table to move the body to a tool loading station and connecting the tool to the second gear of the dental device. Also in the preferred embodiment, the first and second gears are lubricated.
The method can also include the step of advancing the table to move the body to an inspection station, and inspecting the angle to determine whether it has been assembled properly. Dental devices that have not been assembled properly are preferably diverted to a rejection container and dental devices that have been assembled properly are diverted to a conveyor to convey the properly assembled angles to a bagging station. At the bagging station, the assembled angles are bagged. It is also preferable to convey the bagged dental devices to a batch-counting device and count the bagged dental devices using the batch-counting device. After a pre-selected number of angles are counted, a batch of dental devices is created. The batch is loaded into a container and conveyed to an unloading station. The invention also preferably includes the step of sealing the container prior to conveying the container to the unloading station.
It can therefore be seen that the present invention overcomes the problems associated with the prior art. The machine and method for mass assembling dental tools provides for rapid and consistent quality production of the dental tools. Problems with worker inattention and deviations in quality control are overcome by the present invention. Moreover, the cost to assemble and package the dental devices is significantly reduced. These and more specific aspects of the invention are described more fully below.